Gear-hobber control



W. F. ZlM MERMANN April 2, 1929.

GEAR HOBBER CONTROL Filed Dec. 24, 1926 5 Sheets-Sheet awueutoz 3391;; Qua le;

April 2, 1929. w. F. ZIMMERMANN GEAR HOBBER CONTROL Filed Dec. 24, 1926 5 Sheets-Sheet awwwwtoz April 2, 1929. w. FhzlMMERMANN GEAR HOBBER CONTROL Fild Dec. 24, 1926 5 Sheets-Sheet NNN QN MNN April 2, 1929. w. F. ZIMMERMANN 1,707,546

' GEAR HOBBER CONTROL Filed Dec. 24; 1926 5 Sheets-Sheet 4 awuauto'c $3M Sum,

WZTMM April 1929.

w. F. ZIMMERMANVN GEAR HOBBER CONTROL Filed Dec. 24,, 1926 5 Sheets-Sheet avwentoz Patented Apr. 2 j

WILLiAM r. ZIMMERMANN, or MAPLEWOOD, New JERSEY, assrenonf'roeounnaj v 'EBERHARDT, or NEWARK, NEW JERSEY, AoonroRATIoNoFivEw JERSEY.

GnAR noBBna CONTROL.

Application filed December 24, 1926. Serial no. 156516, 5

This invention relates to a control system for bobbing-machines; its ain being to in crease the productivity ot such machines by providing a triple-function. feed-stop; to

5 wit, which.automatically stops the feed,

which automatically suspends visible ,-mo

' tion of other parts and thus announces the,

conclusion of the work, and which automatically conditionsthe machine toriminediate; V

-;ainple such asin my earlier application No unloading and reloading.

In my earlier applicationlNo. 734,487, filed August 27, 1924:, therewas disclosed acontrol system then thought to' reduce the necessary manipulations of the user to an irre ducible minimum, That earlier system appeared to answer'all requirementsof' a spur-f gear hobber but it was not practical. fora helical-gear hobber, and a study 0t that special problem ultimately led to the ;mechan-' ical solution proposed in my subsequent application No. 4,207, file'dJanuary 23, 1925," which consequently, was addressedspecifi, cally to machines foricutting helical gears, That later application was predicated upon a unique combination of a helical hobber 'with a control peculiarly compatible therewith and intimately related thereto; the resultantetlect of the combination ail'ording automatic, as well as manual, manipulation ofthe running of the machine without disturbing tl ierelationships between the. several variables for producing the helical 'ellect.

I subsequently discovered that that solution, although originally supposed'to be of significant utility only in connection w ith helical gearehobbers (Where correlation-Joiall. rotations must be preserved)[couldibeap plied with marked advantage to spur-gear hobbers'not involving the need for correlation preservation in the sense of helical-gear hobbers. It thereby was perceived that that solution had a scope broader than originally I was apparent and hadla greater range of utility than seemed initially possible for the reason that it was-devised with the particular objectof meeting a condition peculiar to from that'helix generating combination, its

the spur-hobbing type. In spur-hobbers-tlie.

special control means may. enter into combination advantageously with organizations of feed alone maybe arrested, providing the relation betweenvtherotations of the Work and;

@lltter spindles be maintained without alter ations, but, fron the standpoint of the-user,

it is desirable amongother capacities of the.

control system, andlas will. be explained, to

make simplev provision for a quickly avail able simultaneous-1arrest oftlie feed aswell' asjthe rotationofthe spindles. x 1

Thisapplication. will, accordingly, be devoted to slioWinghow an i nproved control system for spur-gear hobbers (as for I ex- 7 34,487, filed August- 27, 1924:), may be i111? 'provedjstill more notably by resortingitothe the vigilance of the user. Soner or later, the

user wouldnotice that the tool had ceased to feed; He would. then stop the machine, by manipulating (inappropriate lever, and unloadand reload the machine, and start it on its next batch ofblanks. it

. Now the feedisa slow movement particularly noticeable, especially if the attentions ofthe user are required to be distributedamong two or inorev machines. so. the feed may automatically have been stopped for some time and yettothe eye, o fa user standing a few yards away themachinewill appear, to be in normal. operation torthe' cutter and other partswillbe revolving, the

coo1ant flowing, and its humgbeing heard. This n' ean'sv loss of time and, inthe aggregate, a considerable lag i i. production; a, all [of which has heretofore been. regarded as unavoidable.

l/Vhen the feed stoppage is.noticed,;the user goes to the machine for thepurposegoi removing. the finished spur-gears I and for,

' substituting fresh blanks, A manipulation" precedent to 'doing that the throwing of the lever that; stops the cutter, etc. This again takes acertain amount of -time. i But' the. above md cated. times-losses are eliminated by the combii ationl lierein dea,

scribed foftlieautOliitiljiC stop; appliesnot: only to the feed but also, to: such other el'e i ments as needftO bei stopped to' enabletlie user 'lJOQElCCOHlPllSh a ork re placement I and,

,as the. rotations of these other elements are T 'v'erynotic'e'able tothe' eye, and their cessation likewise, it :s'uflices for-amereiglance to notify .even ad st ntlaaendantaaiihe nudes? l quires blank-replacement. reduced in that particular Time leakage is and time is also saved by sparing the userthe otherwise extra manipulation of throwing a manual lever to stop th ,c utter, etc. preparatoryto removing the work and inserting a fresh blank.

Fig. 1 is a side elevation of spur-gear hobbing-machine showing a fixed work-spindie and a shittable stanchionsupporting a head slidable thereon which carries a hobspindlemountedat a major'angle of ninety degrees andadjustable plus and minus therefrom'thro ugh the minor incidental angle of the cutter. Figs. 2 and'S are rear and front end-elevations of the machine. Fig. l is a skeleton ofthe transmission system and control levers for performing the. various movements ,ofthe working and positioning elements of-the machinef Fig. 5 is a modification of the hob mount. Fig. 6 is a sectional detail of a' friction. coupling between the prime-mover and a part of the transmission system. .Fig. 7 is aside elevation in detail of a portion of theinterlocking control sys tem for the'quick traverse and feed for the hob-carrying head. Fig. 8 is a condensed fragmentary side;elevation of the means actuated by the cutter-slide for automatically operating ,themanually-ope "able levers for controlling the feed and the quick traverse.

Fig. 9 is a'detail ot-the spring snap clutch for throwing in and out the, feed transmission. Fig. 10 is a detailof the spring-detent for urging the feed hand-lever into either one orthe other of its alternativepositions. Fig. 11 is Jan end-elevation of said levers. Fig-l2 is a sectional-elevation, through line 1212 of Fig. 4 showing an interloclrfor enabling the user manuallyto swing the main control lever from its stop to its start position; andshowing also spring-operated means combined with means for releasing said interlock to enablesaid spring-operated means to perform the operation of throwing saidlever into its stop position.

The bed ,A,'in this embodiment. is elongated and positioned horizontally and provides a forwardworking region in whichthc work spindle is directly journaled so as to occupy a fixedposition, and thebed provides also a rear mechanism supporting, region on which the'stanchion is slidablymounted. Thework spindle W is shown journaled in fixed bearings A and it extends downwardly into the interior or the bed as indicated by W and, at its lower end carries a worm-wheel by which it is driven, The portion of the bed that housesthe wormrwheel .l/V is appropriately enlarged to contain that wheel, and inasmuch as the Wheel occupies a fixed position in space, the bed admits of being ribbed and reinforced closely to the Wheel and thus made very rigidas will'be understood without illustrati'on'. It is noteworthythat by thus giving the workspindle a fixed-position at the forsubstantially as solidly as though it other as often happens when the work spindle is shittable in position. 7 The mounting of the spindle is accomplished in a very solid man- .ner wlth the ob ect of realizing the effect of an anvil so that it virtually supports the work was clamped to the bed itseli y and. in consequence, the tendency to vibrate to a minimum.

The stanchion S is in the nature eta heavy box-like castingwhich is provided with slideways S and S at right angles to one another; the slideways S resting on the slideways S provided by the surface of the bed and arranged to permit the heavy stanchion to he slid towards and away from the axis of the worl: spindle for the purpose ol determining the diameter of the gear G to he cut by the machine. The purpose of the transverse slideways S is to support and guide a head H which is thus shiiftable in parallelism with the axis of thework spindle so that the cutter or hob (which is carried by the head) may in'the course of the feeding movement cut the teeth 01" the gear G.

and chatter is reducer,

It will'be understood that this head H is suitably gibbed to the slideways o and, in

order to counterbalance'the weight of the;

head H, a counterweight H may be arranged to rise and descend inan appropriate well provided by the stanchion S; conventional ropes and pulleys It 2 and H being provided as will be understood.

t is to be noted that the stanchion being heavy and massive is ineflect a Jart of the V a l solid bed itself because when clamped down to that bed, it becomes very sohd therewith owing to the action of theclamps augmented by the weight of the stanchion and'by reason of the fact that the base ofthe stanchion S is very extensive so as to resist effectively such overturning forces as resultfrom the pressure oi the hob against the work during the tooling operation. It. willv likewise be noted that the stanchion requires to b shifted only when a change is to be made in the diameter of the gears being cut which ordlnarily would construction avoids the objectionable overhang which is necessitated whenever the worn lit) spindle is mounted on a carriagewhich slides s on the bed.

The transmission system the work spindle and the hob, and tor progressively feeding the head 1H audi or shiftfor rotating both for a single thread hob, and correspondingly 40 v ing the position of the stanchion S, and for varying the rates of rotations and for shifting I the parts quickly. or slowly as the case may 1 e,-

will now be described.

This transmission is in the nature of a balanced drive and comprehends an intermediate l splined shaft'X and two main transmission shafts Y and Z; shaft Y being also splined.

These two shafts are disposed at right angles and the interme'diatefshaft is, parallel with receives the power in the first instance; this being accomplished by the power line c'onsi'stauton'iatic. stop for discontinuing further ing of a pulleyor other primemover, a friction clutch, the powershaft P anda-ppro! pri'ate gears such, for example, as thetwospur gears P and and thet-wo angle gears P- and P The spl ned. transmission shaft Y is ournaled in the sliiftable stanchion so'as bodily to travel therewith and at its lower end is provided with an angle gear 3 which mesheswithan angle gear at which is splined to the:intermediateshaftX.

- For spur-gear production, the, machine'is so made that the" cutter C is mounted ona spindle 0 which is j ournaled in the head at a fixed ma or angle of 90 degrees, but in order to provide for a slight plus and minusvariation of that major angle, slopi'ngeither to the struck about the axis 102 of .a' worm 103;

The minor angle adjustment will be, plus and minus, in the neighborhood of five degrees greater for multiple-thread hob.

The immediate drive comprises a Worm{ wheel lOat, the worm 103 and a co-axial bevel 105, and a bevel 106, splined to the verticaltransi'nission shaft Y; giving the'a-d ustable ings; V I 7 he lower horizontal non-splined transmisright-angled i-geardrive shown'by thedrawsion shaft Z'is journale'd in'the bed of the 7 machine and has aworm 2 affixedthereto for driving the work-spindle W through -th V characteristicef the arrangement-of thisf worin-wheel W. The two pairs of change gears m and 2 and107, and=108,]establish the driving relation between the intermediate to the'work spindle, and likewise six gears 104i, 103, 10.5, 106, 3 and m transmit the-mo- Further details will be tionrtothe cutter. described in connection with'an'explan at on of the manipulations of the machine.

he controls for thehobber, will-now be explained. These provide for preliminary adjustments such as'setting the hob at. the rei. WVhe'n thehob has run quired'distance from the axis of the work to cut a gear of the desired diameter, and also after the whole system is set andstarted'in itsfixed ratios, of movements, before thehob for readily getting the hob close to the end of i the blank sothat'it will not have to travel far,

comes liltd'QIlQflgQll'lGHtWith the blank and travel of the cutter-head;v

through the blank,

The machine,

I After thehob has completed its work, and

after theiinished gear 'has'been' reinovedfrom the work-spindle, it is desirable .to return the hob to its starting point without undueloss oftime, and a quick return control isprovided operation repeat the cycle.

wheel V (provided with graduations or micronieter ad ustments)v is aiiiXed to a shaft that carries an angle gear V which meshes with an angle gear V which in turn is splined for thisjpurpose Theuser'may then insert 4 a fresh blank and set the mechanism again in to tlie screw S 'which runs through the fixed 7 nut N and causes the screw to translate bodily; this translation being communicated to the stanchion by means 'of an appropriate lug, or part S journaledto the screw. This man'- we ual means enables the user very readily to bring the, stanchion to any desired position with 'espectto the work-spindle for cutting.

gears of predetermined diameters.

To start the machine the power lever B is actuated. This shifts the collar '8 and slides a long key 9 whichisftranslatably countersunkin the shaft P:

friction clutch (not shown) between the prime moverl. and the shaftPfl The tra ns-f mission elements previously. described are then maintained in motion by the'power, and the cutter and the workaife both revolved and I fedat the co-relative rates determined byt-he two change gears '2 108, 1O7 and W A.

) and this keyactuates a leveris that it is unidirectional ininanpulaton, i; 'e.,it may be moved hand to start the machine but, when so moved, 111 is held catch against being manually shifted, back again, so that, to stopthe machine, the

starting lever must be released from the hook bymeans tobe later referred to.

dies hasbeeii described. The motion for feedingthe hob is conveyed by atransinisson con sisting of'an angle gear '1 mounted on the shaft Z and meshingwith a.nangle gear 2 a'fixedf tothe shaft A vvo iiii 4 onthat shaft drives siliently determine the position of the rock-,

shaft on and this motion will be correspondingly imparted to the rock-shaft 0, which carries the part 1 provided with the aforesaid yielding detent 79 to throw the sleeve clutch 1" impositively into operative position and provided also with the lug to throw it positively out. Thus it will be seen that, when clutch QPI isin either'its right or its left engaging position, clutch ris disconnected, and' when clutch r" is engaged, clutch Q, can be onlyiniits neutral nontransmitting position. Therefore, by pull ingout pin 5/ and by depressing the lever r a, the feedis disconnected and the quick traverse is accomplished andthe 'head H moves down rapidly. a

To shift quickly land-upwardly the cutter head, the lever a is raised to the upperLdOtted position shown by Fig. 11. -The inter-; look again insures that the feed will out so that when the clutch Q, is moved into its motion reversing position,the transmission will take place through the-quick traverse means and the head will go up rapidly.

' To ustlthe limits of the quick traverse travel of the cutter head,this invention provides a shift-rod T pivoted to the free end of an arm a extendingto the right (as shown rod T will rise, and conversely. if said rod T be pushed down, the effect willbe the sameon the control mechanism as by Fig. 11) from the pivotof the hand-lever a so that, when lever a is despressed, the shift Hence if the user had pulled up the handlever a.

Now, adjustab-ly bolted (by slot'lO and bolts 11) to the cutter-head H is a cam-plate ,7

D. This has an inclined face 12 and within the pathof travel. of that face will be (when the quick down traverse ison) the finger 16 on'the end of the lower arm of a bellcrank lever E which has a fixedpivot at 1 5. The shift-rod T is pivoted at its upper end 14 to the other arm of that bell-crank lever;

Tence, when the shift-rod is raised (to produce a quick down-traverse) the finger 16 will be in the path of the cam-plate D. If now the cutter-head descends, the inclined facev non-slopingfaee 13 of thecam-plate D, the

hand-lever a isin its mid-position as shown in full lines by Fig. 11. Hence the detent f of the feedhand-lever it will now be able (when actuated by the user) to enter the notchin the surface a and the down-feed of the cutter head will besubstituted for. the down quick-traverse. The cutter is now about to enter the work. at a feed rateonlyand cut the gear-teeth. If now the user should try, through a mistake, to push down the hand-lever a, he would beprevented by the finger 16 whichis now riding alongthe 1 non-sloping face 13. Therefore, the. downguick-traverse is limited (by adjusting the initial position of the cam plate D) and the user cannot commit the error of causing the than that of the normal feed.

To adjust the limit of the upward quicktraverse, the collar or dog-T is set at the I appropriate point on the rod Tisothatthe projection H (affixed to the cutter-head) wlll engage said collar and move the traverse '75 cutter to enter the work atany rate faster rod T upwardly and thereby depress the hand-lever a from its raised into its neutral position. This will stop the travel of ithe cutter-head.Hbecause the'detent shown by [Fig 10- will hold the hand-lever k in-the dotted line position shownby Fig.1 11jun-,

til it is actuated by hand.

To limit the extent of feed, there is an adjustable collarr33 on the feed shift-rod 34 V which controls the position of the hand-lever 109 aswill be understood. Also, as amatter manently, affixed to the respective rods 'T of precaution, collars T, 36 and 37 are peri Y and 34 to prevent the user from: making any adjustments beyond the maximum scope. H

of travel provided for the cutter head H.

The shift-rod 34, being pivoted to the arm 115, will turnthe shaft- 113 counter-clockwise, as viewed byFig. 12, wheneverthe projection H on the descending head H meets and pushes down the collar 33. This will release'the catch 112 and permit the springplunger':117 to snap open the master clutch in the main pulley P and thus stop the en-- tire machine; excepting of course the auxil-.

iary'quick-traverseline from Q to the re verse gears Q} andQ, which idlewith the prime-mover P. The user Wlll, of course,

so adjust the collar 33 on the shift-rod 34 that the hob will ha'vefed, automatically .entirely clear of the blank before the drivesystem .isautomatically stopped as described.

The attendant, upon the conclusion of the out, will remove the blank from: thestopped work-spindle Upon lifting the lever aand clutching the then-idling gear Q, to the then- I still, shaft pF, the cutter-head will rise quickly to its ,initial position until arrested by the push ofthe projection H, against the collar T The attendantcan then mount a fresh blank on thethen-still work-spindle.

Upon depressing the handle a, the hob willv be moved quickly towards and stopped.(by

the cam D) near the upper end of the blank.

The lever B is then operated: to close the I master-clutch and the handle his then actuthat others can, by applying current knowledge, readily adapt it for various utilizations by retaining one or more of the features that from the standpoint of the prior art, fairly constitute essential characteristics of either the generic or specific aspects'of this invention, and therefor, such adaptations shouldbe, and are intended'to be, comprehended within the meaning and range of equivalency of the following "claims- Having'thus' revealed this invention, 1 claim as new and desire to secure the following combinations and elements, or equivalents thereof, by Letters Patent offthe United States "1, Ahobber combining a hob-spindle; a slidable head therefor; a work-spindle; a prime-mover; a frictional master-clutch; a

I drive-system deriving motion from said friction clutch and comprising a transmission extending from the one spindle to the other for establishing the rotational ratio therebetween; a branch transmission for sliding said head; positive means deriving motion from said drive system for slowly driving said. branch transmission to feed said head; an impositive meansderiving motion from said,

prime-mover and interchangeably available for more rapidly driving said branch transmission to cause a quick-traverseof said head a control system for automatically rendering said impositive meansimpotent to traverse said head in the portion of its" path utilized during the actual hobbing action; and an interlock for prohibitingthe utilization of said positive means while said impositive means is potent.

2. A; hobber combining a hob-spindle; a slidable head therefor; a work-spindle; a drive-system comprising a transmission e2;- tending'from the one spindle to the other for establishing the rotational ratio therebetween; a branchtransmission for sliding said head; a first-means for positively and slowly driving said branchtransmission; a second means interchangeably available for more 'apidly driving said branch transmission to cause a quick-traverse of said head an inter lock control system for automatically ren dering said first means impotent to feed said head when said second means is set-in action, and for permitting said first means to be utilized when said second is out, and an independent trip mechanism for automatically disconnecting said drive system from the source of'motion when said head has carried thelhob through the blank.

8. A hobber combining a work-spindle; a hobspindle; a slidable head for one of said spindles; transmission elements for rotating said spindle and feeding said head;-a prnnemover; a clutch of the impositive type; a

handlever adapted to render said clutch effeetlve to drlve said transmission elements; a

for enabling it to release said latch andrender said clutch ineffective.

4;. A hobber combining a work-spindle; a hob-spindle; a slidable head for one of said spindles; transmission elements for rotating said spindle and feeding said head; a primemover; a friction clutch; resilient means urging said clutchopen; a lever adapted to be operated manually to overcome said resilient means to render said friction clutch effective to drive said transmission elements; latch means for preventing said hand-lever from swinging reversely to discontinue said drive; a second hand-lever; and mechanism foren-' abling it to render. said latch-means ineffective and thereby permit said resilient-means to open said friction clutch.

5. A hobber combining a worl'r-spindle; a v I J1 I" hob-splndle; a slidable head ior one of said spindles; transmission elements for feeding said head and rotating said spindles; a primemover for simultaneously driving said elements; a friction clutch; resilient means urgmg said clutch open; a latelndevice for holding said means in a position such that saidfriction clutch is closed; and a trip mechanism operated by said slidable head for releasing said latch-device to permit said resilient means to open said friction clutch.

6. A hobber combining a hob-spindle; a,

slidable head therefor; a work-spindle; a transmission extending from the one spindle to the other for establishing the rotational ratio therebetween; a prime-mover; a clutch;

a branch transmission for sliding said head;

a first means deriving motion through said i clutch for positively driving said branch transmission and simultaneously said spindle-driving tronsmission; a second means interchangeably available for more rapidly driving said branch transmission to cause a quick-traverse of said head; an interlock control system for automatically rendering said first means impotent to feed said head when said second means is set in action, and for permitting said first means to be utilized when said, second is out; a first trip mechanism for rendering said second means ineffective before said branch t'ansmission has carried said head into the hobbing region; and an independent trip mechanism for automatically disconnecting said clutch when said head has carried the hob through the blank.

7. A hobbercombining a hob-spindle; a slidable head therefor; a work-spindle; a drive-system comprising a transmission extending from the one spindle to the other for establishing the rotational ratio therebetween; a prime-mover a; first clutch for connecting it with said drive-system; a branch transmission for sliding. said head; a'se'cond clutch. for positively relating said branch transmission to said drive-system; areversing clutch; meanscontinuously driven by said prime-mover adapted to be connected through said third clutch with said branchtransmission to cause a quick-traverse of saidhead; a trip mechanism operated by said slidable head for so controlling said. reversing clutch that 'it can cause the head to descend feeding action thereof; a prime-mover; a friction-clutch; a hand-lever ior closing said friction clutch to connect said prime-mover only when the hob is out of contact with the blank said trip mechanism being adapted to open said first clutch at the conclusion of the.

hobbing operationy and an interlock for versing clutch is closed.

openin said second clutch whenever said i'e- 8. A spur gear hobber combining a rotatable hob-spindle; a rotatable work-spindle;-

a feedable head for one oi said spindles; a

general transmission positively actuating said parts simultaneously at tooling rates; a prime-mover; a master friction-clutch; means operable either automatically by said head. or manually for opening said frictionclutch; and a hand-lever for closing said.

friction-clutch to cause said prime-mover 1mpositively to drive said general transmission:

9. A. spur-gear hobber combining av rotatable hob-spindle; a rotatable work-spindle; a feedable head for one of said spindles; a general transmission positively actuating said parts simultaneously; a prime-mover;

a master friction-clutch ,two hand-levers, the first for closing and the second for opening said friction-clutch; and a connection for. enabling said teedable head at a-vpiedeten 'mine'd station to operate said second lever! automatically.

10. A spur-gear hobbercombining a hob spindle; a: work-spindle; a normally idling but continuously driven transmission terminating ina reversing nechanism; a general transmission for relatively rotating and feed.-

ing the spindles; a positive-clutch in said general 'tI'ELIlSIDlSSlOII for discontinu ng the with said general transmission; another lever operable manually and automatically to disconnect said friction-clutch; and a third-lever adapted first to open said positive-clutch and then to render said reversingmechanism operable to transmit motion from Y said continuously-driven mechanism in either direction. I v

11. A; spur-gear hobber combining a pair of spindles; a feedable-head for one of said spindles; a transmission extending continuously from the one to the other for permanently maintaining the rotational ratio predetermined by a. preliminary setting and having abranchrtransmission leading to said head; a positive-clutchior isolating said branch-transmission from said first transmission; a. fast-runningtransmission; a motion- ,rev'erser for disconnectingor connecting the latter with the branch-line transm1ss1on;a

lever shiitable to occupy either one of three positions to "control said motiona'everse; a second lever; for controlling said 1 positiveclutch; a master,friction-clutch; a third lever for closing said master friction-clutch; a iourthlever for opening said friction-clutch; and mechanism adapted to be actuated by said fee'dable head for operating said fourth lever automatically.

12. A. spnr-gearhobber combininga con- 1 tinuously running prime-mover; a main said system; an auxiliary transmission, contransmission system; a master-clutch there-' between; Work and hob spindlesadapted tobe simultaneously" rotated and translated bytinuously driven by said prime-mover ineependently of said master-clutch; an auto.-

inatic throw-out forsaid master-clutch; and control'means enabling said auxiliary transmission to accomplish arapid relative translation between said spindleswhen said main transmission. system is ineiiective to. efiiect its translation between said spindles.

18,-A spur-gear hobber combining two spindles rotatable and translatable relative 1y; means connectible therewith tor accent plishing said translation rapidly; a lever adapted when moved in a given direction so to connect said means as to enable 'itto trans-V late one of said spindles rapidlyin said direction a trip for automatically disengaging said means ata predetermined station in the advance of said translation; a frictional mas-v ter-clutch, means connectible therewith ioi' slowly continuing said translation; manual means for reversing the direction of said translation; and an interlock forsubstituting said first-mentioned for said second-mentioned means when said reversing means has been resorted to. 1 I

14; A hobber combining a hob-spindle; a 'slidable head therefor; a-worltspindle; a drive-system comprising a transmission extending from the one spindle to the other for establishing j the rotational ratio therebe tween; and including a branch transmission for slidingsaid head; a prime-mover; a master clutch for connecting it/Witli said drive-f clutch for connecting it with said drive-system; a branch transmission for sliding said head; a trip mechanism operated by slidable head for opening said master-clutch to discontinue the rotations of both of said spindles and to arrest the sliding of said head; a quick-traverse clutch; and mcans'eontinuously driven by said prime-mover adapted to be'con ccted through said quick-traverse clutch with said branch transmission to cause a quick-traverse of said head. 16. A hobber combining a hob-spindle; a slidable head therefor; a work-spindle; a drive-system comprising a transmission extending from the one spindle to the other for establishing the rotational ratio therebetween; a prime-mover; a frictional master clutch for connecting it with said drivesystem; a branch transmission for sliding said head; a trip mechanism operated by slidable head for opening said master-clutch to stop the head and both spindles; a reversing clutch; and means continuously driven by said prime-mover adapted to be connected through said reversing clutch with said branch transmission alone to cause a quicktraverse in either direction of said head.

- 17. A hobber combining a hob-spindle; a slidable head therefor; a NVOlli-SPlDtllG; a drive-system comprising a transmission extending from the one spindle to the other for establishing the rotational ratio thereb tween; a prime-mover; a frictional master clutch for connecting it With said drivesystem; a branch transmission for sliding said head; a second clutch forpositively relating said branch transmission to said drive system to start or stop the feed of said head; a trip mechanism operated by slidable head for opening said master-clutch to stop automatically the drive-system and-parts deriving motion therefrom; a reversing); clutch; and means continuously driven by said primemover adapted to be connected through said third clutch Withsaid branch transmission to cause a quick-traverse of said head.

18. A bobbing-machine combining a rotatable hob-spindle; a rotatable Work-spin-- dle; supports therefor incl he; a feedable .iead for supporting the cutter and the Work in a var1able relation; a general transmlsactuating said parts tooling rates; a prime-mover; means to connect'zmd disconnect said transmission with said prime-mover; quick-traverse mechanism for quickly varying the relation between the Workand cutter; and a control system adapted to be manually and automatically operated, 1st manually to start the quick-traverse forwardly, 2nd automatically to stop it when the cutter is about to perform a tooling oper ation, 3rd manually to start the'feed mechanism-Whenever the cutter is toperform a tooling operation, 4th automahcally to disconnect said transmission to stop the rotation and feed when the cutter has performed its operation, 5th manually to start the quick-- traverse reversely, and 6th automatically to arrest'the return operation of the quicletraverse mechanismat a predetermined point.

19. A hobbing machine combining a rotatable hob-spindle; a rotatable Work-spindle; supports therefor including a feedable'head for supporting the cutter and the Work in a variable relation; main transmission for positively rotating simultaneously at tooling rates; a branch therefrom available for causing said head to feed; a pri1ne-mover; means to connect" and disconnect said main transmission With said prime-mover; an auze iliary quick-traverse mechanism available for quickly shifting said head; and a control system adapted to be manually and automatically operated, 1st manually to start the quick-traverse forwardly, 2nd automatically to stop it When the cutter isabout to perform a tooling operation, 3rd manually to start the spindle rotating and feed mechanisms Whenever the cutter is to perform a tooling operation, th automatically to disconnect said transmission to stop the rotation and feed when the cutter has performed its open ation, 5th manually to accomplish a reverse quick-traverse While the spindles are non-ro- I tating, and 6th automatically to arrest the returnoperation of the quick-traverse mechanism at a predetermined point. r

In Witness whereof, I have hereunto sub scribed my name.

WILLIAM F. ZIMMERMANN. 

